China’s Three Gorges Dam 'Catastrophe' warning

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The BBC carries Wang’s comments, and a rather large set of related links. The article also contains a diagram of the dam, which shows how complex the dam is. There’s a ship lift that can take freighters, a lock system, and the massive wall. It really is quite an accomplishment.

Xinhua’s article is pretty scary, and relates to China’s response to a Wall Street Journal piece which raised the concerns about the dam last month. China has been surprisingly frank in its response to those concerns. There are major problems. The dam, according to the Chinese experts, is doing what it’s supposed to do, for flood prevention, and power generation, but the environmental problems are quite serious, and the dam itself is causing some real worries.

The dam contains the flow of the Yangtze, one of the world’s largest, and historically most ferocious, and currently most polluted, rivers, and the problems are large, too.

1. The reservoir itself is polluted.
2. Yangtze water quality, already suffering from severe, “irreversible” pollution, has deteriorated, with increasing growth of algae and aquatic weeds.
3. The sides of the dam are steep slopes. Erosion caused by the sheer mass of water is causing landslides.
4. The landslides have already caused waves 50 metres high, according to sources quoted by Xinhua. (The Aceh tidal wave was 15-30 metres. Krakatoa was 37 metres.)
5. 36 kilometres of shoreline has caved in, and there have been 91 collapses.
6. Water discharged from the dam has damaged embankments downstream.

There are so many issues related to the Three Gorges it could start its own library. It’s the biggest dam in the world, and it’s never been anything but controversial since it started. Some time ago it was alleged that the dam was being built with inferior materials, with contractors and officials rorting the budget and skimping on quality. There was considerable outcry over the flooding of an area containing ancient villages, and historical relics and tombs. In January some money for the project also became a bit more liquid, and has disappeared.

The dam, ironically, given the global criticism of China’s pollution problems, is also a hydro electric scheme, and it is generating electricity and cutting emissions. Murphy’s Law seems to apply to anything environmental in China. Even when they’re doing the right thing, something becomes a problem.

As an engineering feat it hasn’t been boring, either. What’s fascinated me is how they figure the load stresses of water which contains a lot of materials in suspension, like clay. Water is heavy enough, but suspensions are heavier. The dam is 186 metres high. That’s an awful lot of suspension. If the material sinks, it starts to fill the dam. If it remains in suspension, it’s heavy. So far the dam’s been working properly, even in flood season.

CNN has a background article, written prior to the current crop of problems, which gives a good look at the basic issues of the dam and its construction. It's also a very good indication of how ambitious the project was from its inception, and gives an insight into how important it is to the Chinese that it succeeds.

Let’s hope it does, because if it doesn’t, the world’s biggest fire hose is being built. If that 186 metres of water decided to move, nothing could stop it. Imagine a 20 storey version of the Mississippi River, going downhill, at full flood. The Three Gorges Dam is 600 km long, and contains a gigantic amount of water. It’d cause earthquakes, and obliterate anything it encountered, due to kinetic energy. It would be the flood equivalent of Mt. Saint Helens, at the very least, and downstream is one of the most densely populated areas on Earth.

If Noah saw something like that coming, he'd build a spaceship, not an ark.